Example: Configuring Classifiers

This example uses the following hardware and software components:

• One switch.

• Junos OS Release 15.1X53-D10 or later for the QFX Series.

Junos OS supports three general types of classifiers:

• Behavior aggregate or CoS value traffic classifiers—Examine the CoS value in the packet header. The value in this single field determines the CoS settings applied to the packet. BA classifiers allow you to set the forwarding class and loss priority of a packet based on the Differentiated Services code point (DSCP or DSCP IPv6) value, IEEE 802.1p value, or MPLS EXP value. (EXP classifiers can be applied only to family mpls interfaces.)

• Fixed classifiers. Fixed classifiers classify all ingress traffic on a physical interface into one forwarding class, regardless of the CoS bits in the VLAN header or the DSCP bits in the IP packet header.

• Multifield traffic classifiers—Examine multiple fields in the packet, such as source and destination addresses and source and destination port numbers of the packet. With multifield classifiers, you set the forwarding class and loss priority of a packet based on firewall filter rules.

This example describes how to configure a BA classifier called ba-classifier as the default IEEE 802.1 mapping of incoming traffic to forwarding classes, and apply it to ingress interface xe-0/0/10. The BA classifier assigns loss priorities, as shown in Table 1, to incoming packets in the four default forwarding classes. You can adapt the example to DSCP traffic by specifying a DSCP classifier instead of an IEEE classifier, and by applying DSCP bits instead of CoS bits.

To set multifield classifiers, use firewall filter rules.

To verify the classifier configuration, perform these tasks:

• Verifying the Classifier Configuration
• Verifying the Ingress Interface Configuration

user@switch> show configuration class-of-service classifiers ieee-802.1 ba-classifier
    forwarding-class be {
        loss-priority low code-points 000;
    }
    forwarding-class fcoe {
        loss-priority low code-points 011;
    }
    forwarding-class no-loss {
        loss-priority low code-points 100;
    }
    forwarding-class nc
        loss-priority low code-points 110;
    }

user@switch> show configuration class-of-service interfaces xe-0/0/10
congestion-notification-profile fcoe-cnp;
unit 0 {
    classifiers {
        ieee-802.1 ba-classifier;
    }
}